Premium
The rate of reaction of methyl radicals with ozone
Author(s) -
Ogryzlo E. A.,
Paltenghi R.,
Bayes Kyle D.
Publication year - 1981
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550130707
Subject(s) - chemistry , radical , ozone , reaction rate constant , photoionization , mass spectrometry , atmospheric temperature range , analytical chemistry (journal) , photochemistry , kinetics , thermodynamics , organic chemistry , ionization , chromatography , ion , physics , quantum mechanics
The absolute rate constant for the reaction of methyl radicals with ozone has been measured as a function of temperature. Small concentrations of CH 3 were generated by flash photolyzing CH 3 NO 2 at 193 nm with an ArF laser. A photoionization mass spectrometer was used to follow the rate of decay of CH 3 at various ozone concentrations. The resulting rate constants could be fit by the expressions\documentclass{article}\pagestyle{empty}\begin{document}$$ k_1 = (5.4 \pm 1.5) \times 10^{ - 12} \exp [(- 216 \pm 80)/T]{\rm cm}^3 /{\rm molec}\,{\rm s} $$\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$$ k_1 = (2.6 \pm 0.7) \times 10^{ - 12} {\rm (T/300)}^{{\rm 0}{\rm .71} \pm {\rm 0}{\rm .34}} {\rm cm}^3 /{\rm molec}\,{\rm s} $$\end{document}over the temperature range of 243–384 K. These rate constants can be modeled by simple transition state theory using reasonable parameters for the activated complex. Use of this rate constant shows that less than 1% of the methyl radicals formed in the stratosphere react with ozone.